Changes in Sex Steroids and Enteric Peptides After Sleeve Gastrectomy in Youth in Relation to Changes in Bone Parameters.

CONTEXT: Sleeve gastrectomy (SG) improves metabolic endpoints but is associated with impaired bone outcomes. OBJECTIVE: To determine mechanisms contributing to impaired bone health in youth following SG. METHODS: 12-month longitudinal observational study in a multidisciplinary tertiary-care hospital, including 64 youth 13-25 years old with moderate-to-severe obesity (51 females); 30 underwent SG and 34 were nonsurgical (NS) controls. SG was undertaken after a combined decision-making process between treatment team and patient. The main outcome measures were fasting blood for enteric peptides, sex steroids, sclerostin, and bone turnover markers (N-terminal propeptide of type 1 procollagen [P1NP] and C-terminal cross-linking telopeptide [CTX]); dual-energy X-ray absorptiometry measures of areal bone mineral density (aBMD) and body composition; high resolution peripheral quantitative computed tomography; measures of volumetric BMD (vBMD); microfinite element analysis of strength estimates (distal radius and tibia). RESULTS: SG had greater reductions in body mass index (BMI) z-scores, serum estrone, and the free androgen index (FAI) (P†≤†.046), and greater increases in sclerostin, P1NP, and CTX (P†≤†.010) than NS controls. Fasting ghrelin decreased in SG vs NS (P†<†.0001); fasting peptide YY did not change. Most changes were driven by female SG participants. Among females (the majority of study participants), after controlling for baseline age and race, reductions in total hip aBMD Z-scores were positively associated with changes in BMI, lean mass, estrone, FAI, and ghrelin, and inversely with changes in sclerostin.. Decreases in total vBMD of the radius and tibia were associated positively with decreases in BMI. Increases in CTX were associated with decreases in BMI, lean mass, and ghrelin, and increases in sclerostin. CONCLUSION: Bone loss after SG in youth is associated with changes in body composition, sex steroids, sclerostin, and enteric peptides. These are potential targets for future preventative or therapeutic strategies.